Creation of orthophotomaps for the territory near Chegdomyn, Khabarovsk Krai

Customer

Cartographic company

Project's objective

Creation of digital orthophotomaps basing on archival imagery in the coordinate system of 1942, with the mean square deviation of 1 meter, in the territory provided with the planned-height information.

Completed work

Work description

I.  Imagery

In this work, materials from the archival and new space imagery of the Khabarovsk Territory, made from 27.08.2012 to 04.05.2013 by satellites - WorldView-1, WorldView-2, QuickBird, GeoEye-1 were used.

II.  Horizontal and vertical tie-in

By the condition of the technical specification, the customer provided the catalogs of the coordinates of the reference points in the coordinate system SK-42 (23 zone). The accuracy of the coordinates satisfies the accuracy of the photogrammetric work instructions for the 1: 2000 scale. The numbers of items GGS-1 correspond to the numbers from the catalog. Item numbers GGS-2 correspond to the numbers from the catalog with the addition of 3.

Using satellite images with the processing level of Ortho-Ready Standard and the coordinates of the reference points, photogrammetric work on the construction of orthophotomaps on a given territory was carried out under office conditions.

The whole range of photogrammetric works was carried out using the “PHOTOMOD version 5.2” software system.

III.  Heights matrix

For the construction of digital orthophotomaps, horizontals were used as a DTM, with a section height of 5 meters, provided by the customer, in the SXF format.

A matrix of heights with a pitch of 5 m was constructed along the contours, in the coordinate system SK-42, zone 23.

IV.  Photogrammetric works

During the work, a project was created for the area of interest. Photogrammetric work on the creation of an orthophotomap was carried out according to the customer’s specifications and included:

• Determination of the position of ground control points on satellite images.

• Thickening of the plan-altitude justification. Performed by dialing tie points. The points of the network were located on flat areas and were combined with reliably identifiable contours;

• External orientation of satellite images: using the coefficients of a rational polynomial (RPC) and ground control points.

• Creating orthophotomaps. Conducted in stages: the construction of the ortho in the images; mosaic stitching; cutting to the set sheets.